The term 'Grim Film Genre' is often used to describe the film genre known as 'NOIR' (4 letters). NOIR is a genre of crime films that emerged in the 1940s and 1950s, characterized by dark and cynical themes, as well as a sense of moral ambiguity. NOIR films often feature stories of crime, corruption, and betrayal, and often feature a morally ambiguous protagonist. NOIR films are often set in urban environments and feature elements of film NOIR such as chiaroscuro lighting, voice-over narration, and flashbacks.